The main emphasis of the section is to use zebrafish as a model organism and molecular genetics as the technique to identify the function of new genes important in human development. The section focuses on isolating embryonic mutations which affect the normal development of the zebrafish ear as well as interfere with its function. Some of these genes will possibly have importance for congenital deafness in humans. The section also is developing techniques for using retroviruses as a tool for large scale analysis of gene function on a genome-wide scale. Current projects involve analyizing 4 mutations that affect early zebrafish ear development. The genes will be cloned and expression analyzed. Additonally, new retroviral vectors are being developed that will allow for systematic screening of gene expression in vivo.